The long term goal of the proposed research is to understand how the human visual system perceives and encodes properties of objects, such as their orientation, position, and motion in space, relative to frames of reference. More specifically, the research tests the implication of a theoretical distinction that is proposed between two kinds of visual implications of a theoretical distinction that is proposed between two kinds of visual reference frames: "world-surrogate" frames and "hierarchical" frames. World-surrogate frames define global reference values for properties such as perceived upright and stationarity, whereas hierarchical frames are used to define such properties only locally in encoding the relation of one perceived object to another. Several major predictions are suggested by this distinction and will be tested. (1) The objective orientation and motion of world-surrogate frames should be systematically misperceived as more upright and motionless that they are, whereas the orientation and motion of hierarchical frames should be veridically perceived. (2) World-surrogate frames should be effective to the extent that they are like an environment (i.e., large, surrounding, and temporally stable) whereas hierarchical frames should be effective to the extent that they are similar to the target object (in color, size, temporal onset, motion, depth, and so on) because "belongingness" is proposed to be crucial to hierarchical frames. (3) Reference frames should not be determined simply by stimulus structure, but by how the observer perceives that stimulus.. (4) Transformations in hierarchical frames should be sufficient to overcome strong tendencies to see an object's orientation and shape as constant. These and several further questions about reference frames will be investigated using speed and accuracy measures in novel applications of several well-known perceptual paradigms, such as the rod- and-frame task (Asch & Witkin), memory for shape at an orientation (Rock), configural interference on orientation and shape discriminations (Palmer), induced motion (Duncker), and configural motion (Johansson). The research is important because it formulates and tests hypotheses that, if true, would change the way we understand orientation, shape, and motion perception. This understanding is crucial, in turn, to being able to diagnose and treat people with perceptual handicaps and perceptual learning disabilities, both of which have substantial impact on their mental health, self image, and ability to function in society.